A Public Warning System (PWS) is a system for warning about disasters and other emergencies. In case of a disaster such as an earthquake, a tsunami, a hurricane and a wildfire, a PWS may timely and accurately publish a warning message to a user to enable the user to take a proper action to protect himself/herself and his/her family from serious injuries or death or avoid heavy property loss. A PWS defined in the 3rd Generation Partnership Project (3GPP) may be applied to different communication systems, for example: a Global System of Mobile Communication (GSM), a Universal Mobile Telecommunication System (UMTS) and Long Term Evolution (LTE). PWSs include Earthquake and Tsunami Warning System (ETWSs), Commercial Mobile Alert Systems (CMASs) and Emergency Alert Systems (EASs).
In an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) of LTE, a basic network architecture of a PWS is shown in FIG. 1 (FIG. 1 is a schematic diagram of a network architecture of a PWS in an E-UTRAN according to a related art). In the network architecture, a Cell Broadcast Entity (CBE) does not belong to a scope of a communication network defined by the 3GPP, and is mainly responsible for formatting a Cell Broadcast Service (CBS) message. A Cell Broadcast Center (CBC) is a part of a core network, and the CBC is responsible for managing the CBS message, including: allocating a serial number, modifying or deleting the CBS message of an Evolved NodeB (eNB), determining a cell to which the CBS message is broadcasted, determining a time when the CBS message is started to be broadcasted, determining a time when the CBS message is killed to be broadcasted, determining a broadcast period of the CBS message, and the like. Besides general functions, an Mobility Management Entity (MME) is also responsible for: explaining a command from the CBC, storing the message from the CBC, providing a CBC confirmation after successfully completing execution of the command received from the CBC, reporting a CBC failure when the command received from the CBC is not understood or executed, and routing a warning message to a proper eNB in an indicated Tracking Area (TA). The eNB is mainly responsible for broadcasting the warning message received from the MME to User Equipment (UE) residing in a related area belonging to the eNB its own. The CBC may be connected with multiple MMEs, and may also be connected with multiple CBEs. The CBC is connected to the MME through an SBc interface. The MME is connected to the eNB through an S1-MME interface. The eNB is connected to the UE through a Uu interface. An interface between the CBE and the CBC is not included within a scope of a 3GPP standard.
During practical networking, network sharing is originated from a solution released by an operating company to alleviate pressure in case of financial strains caused by huge fees for license plates in Europe. It enables operating companies to cooperate in construction of a communication network and simultaneously flexibly manage own parts. Therefore, a network construction period is greatly shortened, and moreover, Total Cost of Ownership (TCO) is greatly reduced. At the same time, network sharing may promote optimal configuration of resources, avoid repeated construction and implement value maintenance and appreciation of assets. Network sharing is becoming an important issue in network construction. There are many implementation methods for network sharing, including access network sharing, which refers to that multiple operating companies have a radio access network in a shared area as well as respectively independent core networks and service networks. Multiple core network operating companies sharing an access network have own independent mobile network Identifiers (IDs) and operating company IDs. CBC sharing may also be considered in a warning system, and refers to that multiple operating companies share the same CBC in an area.
In case of sharing of multiple operating companies, when a warning message is transmitted and killed, FIG. 2 is a flowchart of issuing a warning message in an E-UTRAN according to the related art, and FIG. 3 is a flowchart of stopping a warning message in an E-UTRAN according to the related art, as shown in FIG. 2 and FIG. 3. In the related technology, a CBC identifies an MME to which a warning message is required to be sent; the CBC sends a write-replace warning request message to the MME, the message including the broadcasted warning message and a transmission attribute (including a Message identifier, a serial number, a Tracking Area ID list which is only used at the MME and is used by the MME to select an eNB to which the write-replace warning request message is to be forwarded, and a warning area which is a cell ID list or a Tracking Area ID list or one or more emergency area IDs), the MME starts transmitting the warning message to the eNB, and the eNB determines a cell to which the warning message is to be broadcasted by virtue of warning area information; and the eNB returns a distribute warning message response message to the MME. A kill flow of the warning message is similar, and the CBC identifies an MME to which a stop warning message is required to be sent; and the CBC sends a stop write-replace warning request message to the MME, herein the message includes: a message identifier, a serial number, a Tracking Area ID list and a warning area. The MME sends a kill request message to the eNB; and the MME determines the eNB which is broadcasting the warning message by virtue of the Tracking Area ID list. The eNB kills the warning message which is identified by the message identifier and the serial number and is being broadcasted in an area identified by a warning area ID; and the eNB returns a kill response message to the MME. However, there are no considerations made about a network sharing scenario in the related technology, and an applicable Public Land Mobile Network (PLMN) range of a warning area is unidentified in warning message signaling.
Therefore, in the related technology, there exists a problem that a PLMN range applicable to a warning area cannot be identified in warning message signaling, i.e. warning by distinguishing PLMNs cannot be performed in a network sharing environment.